Effect

In battle

Generations III to IV

When a Pokémon with Overgrow uses a Grass-typemove, the move's power will be increased by 50% if the user has less than or equal to ⅓ of its maximum HP remaining.

Generations V onwards

Instead of boosting Grass-type moves' power, Overgrow now technically boosts the Pokémon's Attack or Special Attack by 50% during damage calculation if a Grass-type move is being used, resulting in effectively the same effect.